The present invention relates to transducing heads for use with magnetic recording media systems, such as hard disc drives (HDDs), and corresponding methods of manufacture.
HDDs typically comprise one or more magnetic media discs, each disc having concentric data tracks for storing data. Where multiple discs are used, a stack is formed of co-axial discs having generally the same diameter. A transducing head carried by a slider is used to read from and write to a data track on a disc. The slider is carried by a head arm assembly (HAA) that includes an actuator arm and a suspension assembly, which can include a separate gimbal structure or can integrally form a gimbal. During operation, as the disc spins, the slider glides above the surface of the disc on a small cushion of air. The actuator arm pivots to movably position the slider with respect to the disc. A microactuator assembly can be included to provide additional precision positioning of the suspension assembly. Electrical connections extend along the suspension to electrically connect the transducing head to components located at or near the actuator arm. Those electrical connections can be formed on the suspension itself, or can be located on a separate interconnect structure supported relative to the suspension, such as a flex-on suspension (FOS).
The transducing head typically includes a single writer and a single reader. The reader includes a sensor for retrieving magnetically encoded information stored on the disc (or other magnetic storage media). Magnetic flux from the surface of the disc causes rotation of the magnetization vector of a sensing layer or layers of the sensor, which in turn causes a change in the electrical properties of the sensor that can be detected by passing a current through the sensor and measuring a voltage across the sensor. Depending on the geometry of the sensor, the sense current may be passed in the plane (CIP) of the layers of the sensor or perpendicular to the plane (CPP) of the layers of the sensor. External circuitry then converts the voltage information into an appropriate format and manipulates that information as necessary to recover information encoded on the disc.
The writer, for a perpendicular recording transducing head, typically consists of a main pole and a return pole, which are separated from each other at an air bearing surface (ABS) of the transducing head by a gap layer. The main pole and return pole are connected to each other at a region distal from the ABS by a back gap closer or back via. One or more layers of conductive coils are positioned between the main and return poles, and are encapsulated by insulating layers. The conductive coils can have different configurations, such as helical and pancake configurations. To write data to the disc (or other magnetic media), an electric current is applied to the conductive coils to induce a magnetic field in the disc under a pole tip of the main pole. By reversing the direction of the current through the coils, the polarity of the data written to the magnetic media is reversed, and a magnetic transition is written between two adjacent bits. Because the main pole is generally the trailing pole of the main and return poles, the main pole is used to write the data to the magnetic media.
The slider includes a slider body (typically called the “substrate”) and an overcoat that includes the transducing head. The overcoat is electrically insulative. A plurality of bond pads are formed at a side or edge of the slider, typically at its trailing edge, for electrically connecting elements of the transducing head to external circuitry through the overcoat. There are generally two bond pads for the writer and two for the reader for a given transducing head.
As areal recording density for HDDs increases, the sizes of sliders and transducing heads continue to decrease. Moreover, the track widths of individual concentric data tracks on HDD discs continue to decrease. Decreasing slider sizes and disc track widths present numerous difficulties. For example, with perpendicular recording heads, magnetization transitions are recorded on the magnetic medium (e.g., disc) by a trailing edge of the main pole. The shape of the pole tip of the main pole is projected and reproduced on the magnetic medium during the write process. However, unwanted overwriting (or side writing) at locations adjacent to a desired write location on a data track may occur due to changes in skew angle as the transducing head travels in an arc across the magnetic medium as the actuator arm and suspension pivot. This can cause adjacent track interference, resulting in off track erasure of transitions recorded on the magnetic medium, and ultimately leading to a degradation of bit error rate.
An area of the pole tip of the main pole of the write is directly related to the ability to induce magnetization in the magnetic media, and writability loss. Prior art transducing heads have utilized a single, symmetric, trapezoidally-shaped (or hexagonally-shaped) pole tip that has two opposed beveled or “skewed” side walls in order to reduce overwriting due to skew angle. These bevels may be configured to have a relatively large wall angle in order to reduce overwriting at large skew angles. However, such a double-bevel trapezoidal pole tip design results in a decreased area of the pole tip at the ABS, particularly with relatively high wall angles for the bevels, which generally reduces a magnetic field H along a trailing edge of the pole tip compared to a rectangular pole tip shape. This reduction of the area of the pole tip and the corresponding loss in writability is undesirable.
Thus, the present invention provides a slider assembly having an alternative transducing head configuration configuration.